docstr: check zero crossing rate on single crossing with a gap
docstr_tok: ["check","zero","crossing","rate","on","single","crossing","with","a","gap"]
code: def test_single_with_gap(self):
      """check zero crossing rate on single crossing with a gap"""
      self.vector[int(buf_size / 2) - 2] = 1.0
      self.vector[int(buf_size / 2)] = -1.0
      self.assertEqual(2.0 / buf_size, zero_crossing_rate(self.vector))
  
file_path: aubio/python/tests/test_zero_crossing_rate.py
imports: from numpy.testing import TestCase
  from aubio import fvec, zero_crossing_rate
label_desc: Use image node_id 7 for calling the zero_crossing_rate_test_case obj's underlying member method code with example usage: obj.test_single_with_gap() without return types